Bluthner Patent Action

[John Delacour]

At 13:31 -0400 29/9/08, John Alsina wrote:

>The following sentence from new translation of the Bluthner 
>regulation procedure may explain much of the difference in touch 
>between the Bluthner and the Erard actions:
>
>The key should be pressed slowly until it comes to contact with the 
>touch washer, and then the hammer should rise a further 1 millimetre 
>before setting off, ...
>
>This makes a big difference between what the pianist feels just 
>before and during let-off on the two types of action.
>On the Bluthner, the key contacts the front punching, and the finger 
>begins to encounter smoothly increasing resistance before 
>let-off.  At let-off, there is an additional "bump" of 
>resistance due to friction between jack and abstract, but it is only 
>a part of the total resistance felt at that point.  Depending on the 
>quality of the punching and the exact let-off regulation, the "bump" 
>felt due to let-off may be almost imperceptible.

The "bump" on the Blüthner action is imperceptible for several 
reasons:  On the Herz-Erard action the jack has to escape from the 
roller against a force exerted in the opposite direction by a roller 
carrying the whole weight of the hammer.  On the Blüthner the notch 
presents no resistance.  Besides that, the hammer is less heavy and 
is made effectively even lighter by the action of the L-spring; 
moreover the jack tail is far longer than on the Herz-Erard, since 
complete escapement requires far less travel under the notch; and 
finally the jack spring is extremely light, hardly adding any weight 
to the touch.  The only way a kick of any kind will be felt is if the 
touch is too deep in relation to the blow; and, as I mentioned 
earlier, the addition of a cloth punching on top of the baize gives a 
more yielding key-bed.

I don't know how they do things now but in the 1980s and '90s 
Bösendorfer used to regulate their grands (with the Schwander type 
action) with barely any after-touch.  How they managed the key-bed I 
can't say, but it must have been fairly yielding.

JD

PS.  Has anyone got the Deutsche Reichspatentnummer for the original 
1858 patent action?  Somewhere I have a photocopy of his patent an 
"improved" version, but I can't find it anywhere at the moment.